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      |本期目錄/Table of Contents|

      [1]花少震,孟凡凈.注塑成型噴射現象的實驗及數值研究[J].西安交通大學學報,2019,53(09):88-95.[doi:10.7652/xjtuxb201909012]
       HUA Shaozhen,MENG Fanjing.Experimental and Numerical Research on Jetting Phenomenon during Injection Molding[J].Journal of Xi'an Jiaotong University,2019,53(09):88-95.[doi:10.7652/xjtuxb201909012]
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      注塑成型噴射現象的實驗及數值研究(PDF)

      《西安交通大學學報》[ISSN:0253-987X/CN:61-1069/T]

      卷:
      53
      期數:
      2019年第09期
      頁碼:
      88-95
      欄目:
      出版日期:
      2019-09-10

      文章信息/Info

      Title:
      Experimental and Numerical Research on Jetting Phenomenon during Injection Molding
      作者:
      花少震 孟凡凈
      河南工學院機械工程學院, 453003, 河南新鄉
      Author(s):
      HUA Shaozhen MENG Fanjing
      College of Mechanical Engineering, Henan Institute of Technology, Xinxiang, Henan 453003, China
      關鍵詞:
      注塑成型 噴射現象 蛇形流 剪切速率 內摩擦
      Keywords:
      injection molding jetting phenomenon snake-like flow shear rate internal friction
      分類號:
      TQ320.66
      DOI:
      10.7652/xjtuxb201909012
      摘要:
      為探索注塑成型充填過程中觸發熔體噴射現象的關鍵性因素,分別采用實驗方法和數值模擬技術,研究了在高注射速率下熔體溫度和注射速率對噴射的影響以及熔體噴射后的形態演化。通過短射實驗研究了不同加工工藝條件下熔體噴射后的流動形態,發現熔體噴射后的形態演化具有較強的不穩定性,短射后制品所呈現的蛇形流形態具有較差的可重復性。采用數值模擬手段,分別再現了短射實驗中具有穩定蛇形流形態和非穩定蛇形流形態的噴射演化過程,發現熔體溫度越高,蛇形流的折疊次數就越多;谌垠w噴射后的形態演化特征,分析出熔體噴射后會經歷柱狀噴射階段、屈曲流演化階段、簡單充填模式階段共3個發展階段,且熔體只要發生柱狀噴射,就具有相同的流動形態。通過分析柱狀噴射階段熔體的剪切速率、黏度、速度和壓力的變化情況可以發現:熔體的剪切速率非常小; 在柱狀噴射前期,熔體黏度比曲線呈平臺狀; 熔體的速度保持恒定; 熔體噴射不屬于壓力驅動流,可近似認為是牛頓流體。研究結果表明,觸發噴射的關鍵性因素是熔體流動過程中缺乏內摩擦,使得熔體的黏性作用非常小,此時熔體流動由慣性驅動,熔體噴射為慣性驅動流。
      Abstract:
      To explore the key factor inducing jetting phenomenon in injection molding, the influences of melt temperature and injection rate on jetting and melting evolution are investigated experimentally and numerically at high jetting speed. The shapes of melt front under different process conditions are obtained and analyzed via short shot experiments. The experiments reveal that the shape evolution is extremely instable and the snake-like stream shapes of the molded parts show a weak repeatability. Then the stable and instable snake-like jetting streams and their evolution are reproduced in the numerical simulations. It is found that: the higher the melt temperature is, the more the folding snake-like streams exist; the evolution of jetting can be divided to three stages - columnar jet, buckling flow, and simple filling pattern; and the shapes of jetted melt almost remain the same in the first stage. Shear rate and viscosity in columnar jet stage are also analyzed. The melt at the beginning of columnar jet can be considered as a Newtonian fluid with a zero-shear ate. While velocity in this stage keeps constant and jetting is not a pressure-driven flow. The lack of internal friction leads a small viscous effect, and melting flow is driven by inertia, then the melt jetting turns to inertia-induced flow.

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      備注/Memo

      備注/Memo:
      收稿日期: 2018-12-25。作者簡介: 花少震(1988—),男,講師;痦椖: 國家自然科學基金資助項目(51605150)。
      更新日期/Last Update: 2019-09-04
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